Substance use disorders belong to the class of externalizing behaviours that are generally more common among men than women. Those women who do have substance disorders therefore deviate more from the norms of society compared with men, tend to live in an environment characterized by high risk of violence and other forms of abuse, and tend to be survivors of childhood trauma. In terms of seeking treatment, women often have difficulty acknowledging their problems with substance use disorders, and professionals are reluctant to ask women about drug or alcohol use. Even when they do seek treatment, women in many countries face practical and financial barriers to access treatment. For women who do enter treatment, outcomes are generally comparable to outcomes for men, suggesting that facilitating entry into treatment can yield substantial benefits for women with addictions.